{"id":78342,"date":"2024-10-16T11:47:17","date_gmt":"2024-10-16T03:47:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/78342\/"},"modified":"2024-10-16T11:47:17","modified_gmt":"2024-10-16T03:47:17","slug":"mysql%e6%8c%87%e4%bb%a4-distinct%ef%bc%88%e5%8e%bb%e9%99%a4%e9%87%8d%e8%a4%87%e5%80%bc%ef%bc%89","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/78342\/","title":{"rendered":"MySQL\u6307\u4ee4: DISTINCT\uff08\u53bb\u9664\u91cd\u8907\u503c\uff09"},"content":{"rendered":"<h1 id=\"mysql%e6%8c%87%e4%bb%a4-distinct%ef%bc%88%e5%8e%bb%e9%99%a4%e9%87%8d%e8%a4%87%e5%80%bc%ef%bc%89-GlDYenvpOE\">MySQL\u6307\u4ee4: DISTINCT\uff08\u53bb\u9664\u91cd\u8907\u503c\uff09<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\uff0cMySQL\u662f\u4e00\u500b\u5ee3\u6cdb\u4f7f\u7528\u7684\u958b\u6e90\u8cc7\u6599\u5eab\u7cfb\u7d71\u3002\u7576\u6211\u5011\u9700\u8981\u5f9e\u8cc7\u6599\u8868\u4e2d\u67e5\u8a62\u8cc7\u6599\u6642\uff0c\u7d93\u5e38\u6703\u9047\u5230\u91cd\u8907\u7684\u6578\u64da\u3002\u70ba\u4e86\u89e3\u6c7a\u9019\u500b\u554f\u984c\uff0cMySQL\u63d0\u4f9b\u4e86DISTINCT\u6307\u4ee4\uff0c\u5e6b\u52a9\u7528\u6236\u53bb\u9664\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u91cd\u8907\u503c\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDISTINCT\u7684\u7528\u6cd5\u53ca\u5176\u5728\u5be6\u969b\u61c9\u7528\u4e2d\u7684\u91cd\u8981\u6027\u3002<\/p>\n<h2 id=\"distinct%e7%9a%84%e5%9f%ba%e6%9c%ac%e7%94%a8%e6%b3%95-GlDYenvpOE\">DISTINCT\u7684\u57fa\u672c\u7528\u6cd5<\/h2>\n<p>DISTINCT\u6307\u4ee4\u7528\u65bc\u9078\u64c7\u552f\u4e00\u7684\u6578\u64da\u884c\u3002\u5176\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT DISTINCT column1, column2, ...\nFROM table_name;\n<\/code><\/pre>\n<p>\u5728\u9019\u88e1\uff0ccolumn1\u3001column2\u7b49\u662f\u4f60\u5e0c\u671b\u67e5\u8a62\u7684\u6b04\u4f4d\uff0c\u800ctable_name\u5247\u662f\u8cc7\u6599\u8868\u7684\u540d\u7a31\u3002\u4f7f\u7528DISTINCT\u5f8c\uff0c\u67e5\u8a62\u7d50\u679c\u4e2d\u5c07\u53ea\u986f\u793a\u552f\u4e00\u7684\u6578\u64da\u884c\u3002<\/p>\n<h2 id=\"%e7%af%84%e4%be%8b%e5%88%86%e6%9e%90-GlDYenvpOE\">\u7bc4\u4f8b\u5206\u6790<\/h2>\n<p>\u5047\u8a2d\u6211\u5011\u6709\u4e00\u500b\u540d\u70ba\u201ccustomers\u201d\u7684\u8cc7\u6599\u8868\uff0c\u8a72\u8868\u5305\u542b\u4ee5\u4e0b\u6578\u64da\uff1a<\/p>\n<pre><code>+----+----------+\n| id | country  |\n+----+----------+\n| 1  | USA      |\n| 2  | Canada   |\n| 3  | USA      |\n| 4  | Mexico    |\n| 5  | Canada   |\n+----+----------+\n<\/code><\/pre>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u6240\u6709\u4e0d\u540c\u7684\u570b\u5bb6\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u6307\u4ee4\uff1a<\/p>\n<pre><code>SELECT DISTINCT country\nFROM customers;\n<\/code><\/pre>\n<p>\u57f7\u884c\u5f8c\u7684\u7d50\u679c\u5c07\u662f\uff1a<\/p>\n<pre><code>+----------+\n| country  |\n+----------+\n| USA      |\n| Canada   |\n| Mexico    |\n+----------+\n<\/code><\/pre>\n<p>\u5982\u4e0a\u6240\u793a\uff0c\u67e5\u8a62\u7d50\u679c\u4e2d\u53ea\u986f\u793a\u4e86\u552f\u4e00\u7684\u570b\u5bb6\u540d\u7a31\uff0c\u91cd\u8907\u7684\u201cUSA\u201d\u548c\u201cCanada\u201d\u88ab\u53bb\u9664\u4e86\u3002<\/p>\n<h2 id=\"distinct%e7%9a%84%e5%a4%9a%e6%ac%84%e4%bd%8d%e6%9f%a5%e8%a9%a2-GlDYenvpOE\">DISTINCT\u7684\u591a\u6b04\u4f4d\u67e5\u8a62<\/h2>\n<p>DISTINCT\u4e0d\u50c5\u53ef\u4ee5\u7528\u65bc\u55ae\u4e00\u6b04\u4f4d\uff0c\u4e5f\u53ef\u4ee5\u7528\u65bc\u591a\u500b\u6b04\u4f4d\u7684\u67e5\u8a62\u3002\u7576\u67e5\u8a62\u591a\u500b\u6b04\u4f4d\u6642\uff0c\u53ea\u6709\u7576\u6240\u6709\u6307\u5b9a\u7684\u6b04\u4f4d\u7d44\u5408\u90fd\u662f\u552f\u4e00\u6642\uff0c\u8a72\u884c\u624d\u6703\u88ab\u8fd4\u56de\u3002<\/p>\n<p>\u4f8b\u5982\uff0c\u5047\u8a2d\u6211\u5011\u7684\u201ccustomers\u201d\u8cc7\u6599\u8868\u9084\u5305\u542b\u4e00\u500b\u201ccity\u201d\u6b04\u4f4d\uff0c\u6578\u64da\u5982\u4e0b\uff1a<\/p>\n<pre><code>+----+----------+-----------+\n| id | country  | city      |\n+----+----------+-----------+\n| 1  | USA      | New York  |\n| 2  | Canada   | Toronto   |\n| 3  | USA      | Los Angeles|\n| 4  | Mexico   | Mexico City|\n| 5  | Canada   | Toronto   |\n+----+----------+-----------+\n<\/code><\/pre>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u67e5\u8a62\u4e0d\u540c\u7684\u570b\u5bb6\u548c\u57ce\u5e02\u7d44\u5408\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u6307\u4ee4\uff1a<\/p>\n<pre><code>SELECT DISTINCT country, city\nFROM customers;\n<\/code><\/pre>\n<p>\u57f7\u884c\u5f8c\u7684\u7d50\u679c\u5c07\u662f\uff1a<\/p>\n<pre><code>+----------+-----------+\n| country  | city      |\n+----------+-----------+\n| USA      | New York  |\n| USA      | Los Angeles|\n| Canada   | Toronto   |\n| Mexico   | Mexico City|\n+----------+-----------+\n<\/code><\/pre>\n<h2 id=\"%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-GlDYenvpOE\">\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u4f7f\u7528DISTINCT\u6642\u9700\u8981\u6ce8\u610f\u4ee5\u4e0b\u5e7e\u9ede\uff1a<\/p>\n<ul>\n<li>DISTINCT\u6703\u5f71\u97ff\u67e5\u8a62\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u5927\u578b\u8cc7\u6599\u8868\u4e2d\uff0c\u56e0\u70ba\u5b83\u9700\u8981\u9032\u884c\u984d\u5916\u7684\u8a08\u7b97\u4f86\u53bb\u9664\u91cd\u8907\u503c\u3002<\/li>\n<li>\u5728\u4f7f\u7528DISTINCT\u6642\uff0c\u6240\u6709\u9078\u64c7\u7684\u6b04\u4f4d\u90fd\u5fc5\u9808\u662f\u552f\u4e00\u7684\u7d44\u5408\uff0c\u5426\u5247\u5c07\u4e0d\u6703\u8fd4\u56de\u4efb\u4f55\u7d50\u679c\u3002<\/li>\n<li>\u5982\u679c\u53ea\u9700\u8981\u67d0\u4e00\u6b04\u4f4d\u7684\u552f\u4e00\u503c\uff0c\u5efa\u8b70\u50c5\u9078\u64c7\u8a72\u6b04\u4f4d\u4ee5\u63d0\u9ad8\u67e5\u8a62\u6548\u7387\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-GlDYenvpOE\">\u7e3d\u7d50<\/h2>\n<p>DISTINCT\u6307\u4ee4\u5728MySQL\u4e2d\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u6709\u6548\u5730\u53bb\u9664\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u91cd\u8907\u503c\u3002\u7121\u8ad6\u662f\u5728\u55ae\u4e00\u6b04\u4f4d\u9084\u662f\u591a\u6b04\u4f4d\u67e5\u8a62\u4e2d\uff0c\u6b63\u78ba\u4f7f\u7528DISTINCT\u90fd\u80fd\u63d0\u9ad8\u6578\u64da\u7684\u53ef\u8b80\u6027\u548c\u6e96\u78ba\u6027\u3002\u5c0d\u65bc\u9700\u8981\u8655\u7406\u5927\u91cf\u6578\u64da\u7684\u61c9\u7528\u5834\u666f\uff0c\u4e86\u89e3\u5982\u4f55\u4f7f\u7528DISTINCT\u5c07\u5c0d\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u7522\u751f\u7a4d\u6975\u5f71\u97ff\u3002<\/p>\n<p>\u5982\u679c\u60a8\u6b63\u5728\u5c0b\u627e\u9ad8\u6548\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\uff0cServer.HK \u63d0\u4f9b\u591a\u7a2e\u9078\u64c7\uff0c\u9069\u5408\u5404\u7a2e\u9700\u6c42\u3002\u7121\u8ad6\u662f <a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a> \u9084\u662f <a href=\"https:\/\/server.hk\">\u4e91\u4f3a\u670d\u5668<\/a>\uff0c\u6211\u5011\u90fd\u80fd\u70ba\u60a8\u63d0\u4f9b\u7a69\u5b9a\u7684\u670d\u52d9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3MySQL\u6307\u4ee4DISTINCT\uff0c\u5b78\u7fd2\u5982\u4f55\u6709\u6548\u53bb\u9664\u67e5\u8a62\u7d50\u679c\u4e2d\u7684\u91cd\u8907\u503c\uff0c\u63d0\u5347\u6578\u64da\u8655\u7406\u6548\u7387\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-78342","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78342","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=78342"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78342\/revisions"}],"predecessor-version":[{"id":78343,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/78342\/revisions\/78343"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=78342"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=78342"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=78342"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}